1. Field of the Invention
The present invention relates to a dosimetry device used to measure the dose distribution of charged particle radiation.
2. Description of the Related Art
A conventional dosimetry device for charged particle radiation is disclosed for example in “A pixel chamber to monitor the beam performances in hadrontherapy,” Nuclear Instruments and Methods in Physics Research, A519, pp. 674 to 686, 2004.
The dosimetry device for charged particle radiation disclosed by the publication includes a high voltage electrode (cathode electrode), an ionization chamber including a spacing frame and a frame having a plurality of anode electrodes arranged in a matrix, and a signal processing circuit that processes a signal from each of the anode electrodes. An ionized space forms between the high voltage electrode (cathode electrode) and each of the anode electrodes, and high voltage is applied between the high voltage electrode (cathode electrode) and each of the anode electrodes through the ionized space. When charged particles enter the ionized space, the air inside the ionized space is excited and ions are generated, the ions are attracted by corresponding anode electrodes, and charge is generated at the anode electrode. The charge at each of the anode electrodes can be read by the signal processing circuit to measure the dose distribution of the charged particles in the ionized space.